Improvement in machinery for threading wood-screws and feed apparatus therefor



T. J. SLOAN.. Making Screws.

Patented Sept. 23, 1851.

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UNITED STATES PATENT OFFIcE.

THOMAS J. SLOAN, OF NEW YORK, N. Y.

IMPROVEMENT IN MACHINERY FOR THREADING WOOD-SCREWS AND FEED APPARATUS THEREFOR.

Specification forming part of Letters Patent No. 8,379, dated September 23, 1851.

.To all whom it may concern:

Be it known that I, THOMAS J. SLOAN, of the city, county, and State of New York, have invented certain new and useful Improvements in the Machine for Threading and Feeding Wood-Screws; and I do hereby declare that the following is a full, clear, and exact description thereof, reference being had to the accompanying drawings, making part of this specification, inv which- Figure 1 is a plan; Fig. 2, an end elevation; Fig. 3, a side elevation; Fig. 4, a side elevation in section, representing the finger motion for presenting the blank to the jaws; Fig. 5, a front view of the same; Figs. 6 and 7, side and front elevations of the cam and leversfor operating the apparatus which supplies the blank to the transferring-fingers;

Fig. 8, a section at the line A B of Fig. 2; Fig. 9, another section at the line C D of Fig. 8; and Fig. 10, a top view, on an enlarged scale, of the cutters.

The same letters and figures indicate like parts in all the figures.

The first part of my invention relates to the method of operating the fingers which transfer and present the blanks to the gripping-jaws of the mandrel. Heretofore the fingers have been operated by only one cam,

which makes one revolution for each complete operation of the machine, for the reason that the fingers are only required to supply and present a blank after a screw has been threaded. From this it follows that either the fingers must be moved very slowly or else the face of the cam which operates them must be so near a radial line as to operate very imperfectly or be made of an impracticable diameter relatively to the other parts of the machine. There is a limit to the size of cam, for it must bear a certain proportion to the other parts of the machine or it cannot be introduced, and if the other parts of the machine be made of sufficient size they will be cumbersome, and the levers and arms will be liable to yield by fieXure. To avoid these difiiculties, this part of my invention consists in the employment (in combination) of two cams, one of which makes but one revolution for each complete threading motion, and another on any shaft which moves withgreater velocity, the first of these camsbeing employed simply to hold up the fingers during the threading motion and to permit them to approach the mandrel when a blank is to be supplied, and the second or fast-moving cam being employed to give the required movements to the fingers, whereby I am enabled to give such form to the said second cam as shall operate the fingers rapidly and by an easy motion.

The second part of my invention relates to an improvement on the method of cutting pointed screws heretofore secured to me by Letters Patent. When one cutter alone is em ployed, it must move along the whole length of the threaded part of the screw, and when more than one cutter has been heretofore employed all the cutters have been made of the same form, and each in succession has been made to follow the same track. The nature of this part of my invention consists in employing two cutters or chasers in combination-one to form the thread on the body or cylindrical part of the shank and the other to form the thread on or at the point--one of them being made to move partlyinto the track of the other, whereby a less range of motion is required, for the one forms the thread on or at the point during the operation of the other; and it will be obvious that either one of the cutters can be made to 'run a little into the track of the other,or the two can be made to run a short distance in the track, the one of the other, to insurejthe making of the thread on the point a continuation of the thread on the main part of the shank.

In the accompanying drawings, a represents the frame, which may be varied at the discretion of the constructor, and b the mandrel, which carries the gripping-jaws in the usual manner for holding and rotating the blank to be threaded. This mandrel receives motion from the cam-shaft c by a cog-wheel and pinion d and e.

f f represents the terminationof the ways of a feeding-machine from which the blanks are delivered, but which may be delivered in any other way, into a recess in a slide g, surrounded by a casing h, in which it works. The slide g is jointed to one end of a rod i, connected with the wrist-pin of an arm j on a hollow rock-shaft 10 by a slot Z and by a spring on. The rock-shaft has another arm n, which is borne down by a spring 0 on a cam 19 on the shaft q, that receives motion by a co wheel and pinion a r from a shaft 5, that in turn receives motion from the cam-shaftcby a pinion t and cog-wheel a. The shaft q makes one revolution for each complete threading motion of the machine, and the.

cam 17 is so formed as to operate the arm n up and down to communicate the desired motion by the arm j and the rod '5 to the slide 9. The slide is carried in to receive a blank by the wrist-pin of the arm j acting against the end of the slot Z, and drawn out to deliver the blank by the tension of the spring m, so as to.

prevent breakage in case of any impediment. So soon as the slide carries out a blank it is taken by a pair of fingers o, by which it is lifted out of the recess in the slide and then with a recess 6, made in a part of" its periphery, and as the shaft makes but one revolution during one entire threading motion the recess 6 is only brought under the projection c of the arm w at the endof the threading motion,- when a new blank is required to be presented to the jaws. There-is a stud-pin f on the side of the arm w, which bears on the periphery of a second cam g on the shafts, which rotates with greater velocity than the cam 61. When the recess e is under the projection of the arm w, the required up and down motions can be given to the arms by the cam g, whichfrom the point 1 to2 in the direction the reverse of the arrow is concentric to hold up the fingers, and at 2 it is slightly recessed to permit the fingers to descend and catch the blank and then to lift it out of the recess in the slide. After the slide has been pushed in the cam from the point 3 to etruns in toward the axis to permit the fingers todesoend and bring the blank in a line with the axis of the mandrel. From 4 to 5 the said cam is concentric to retain the fingers in that position until the blank can be inserted in the jaws, and then-from 5 back to the point lthe cam runs out to elevate the fingers.

In addition to the up-and-down motion, the fingers have a motion toward the grippingjaws to insert the blank, and'then back, the latter'being given by a spring h',which bears against the end of the rock-shaft a, and the motion toward the jaws to insert the blank is given by a cam-face i on .the side of the cam g and extending from the point 4 to 5, as

shown by dotted lines in Fig. 4:, and acting on a lip ofthe-stud-pin f on the arm w.

The mechanism for operating the grippingjaws is not represented and does not require to be described, as it can be constructed and operated on any of the well-known plans.

The two cutters or chasers j and k are mounted on and secured each to separate heads Z and m the one Z on a rocker 'n and the one m on a sleeve-rocker 0', that turns and slides on the first with a helical spring 19' interposed between the end of the sleeve and a shoulder g on the rocker, the tension of which spring tends constantly to force the two cutters toward each other. The two rockers thus united slide together endwise in boxes r r, and are kept against the face of a cam s by the tension of a spring 25. The cam s is on the shaft 0, before mentioned, and makes half the number of revolutions during one entire threading motion that there are chasing operations to complete one thread of a screw, the number being determined by the relative proportions of the cog-wheels and pinions, which proportions may be varied at the discretion of the constructor. The-cam s is what is known as a regular wedgecam, and is double, so as to give aregular progressive motion to the'cutters from where the thread begins toward the poi'ntof the screw, and then permit them to be forcedbaok by the tension of the spring to repeat theoperation.

The cutter j has its front face'made -parallelwith the axis of the screw, or nearly so, and cuts the thread along the main part of the shank,'and its motion toward the axis'of the blank to form the thread is governed by a mold against which the head of thecutt'er slides, the shape of which mold determines the form of the core of the screw when completed. The motion of this mold toward the blank at the commencement of each threading motion and back at the end is not described nor represented, as it makes no. part of my present invention. While the cutter j is cutting the thread along the main part of the shank the other cutter is, which has its front face beveling in the line of the conical point of the screw to becut, is cutting the thread on the conical point, and themotion of this cutter toward the axis of the blank to determine the form of the point is governed by the shape of the continuation of the'mold. As the two cutters operate simultaneouslyone on the main part of the shank and the other on the point, the latter commencing as much after the former as the conical point is shorter than the'main part'of the shank it follows that the range of longitudinal'motion to be given to the cutters is less than where only one cutter is employed. The cutter which forms the thread on the conical point must have an alternately increasing and retarding motion, on the principle secured to me by Letters Patent bearing date the 24th dayof November, 1846. This is effected bya wedge 1), (represented in section in Figs. 8 and 9 and by dotted lines in Fig-2,) which slides in a mortise in the rocker n, and. which acts besme a tween the two heads 7" and 7c. This wedge is forced by the tension of a spring w against the periphery of a cam 00 on the shaft 0. On one side of the axis the said cam has a projection y to force in the Wedge, so that the cutter 70' shall move faster than the other, and on the opposite side of the axis a recess a to permit the wedge to be forced out by the spring that during the next operation the said cutter It shall move with a slower motion than the other. In this way the cutter which forms the thread on the main part of the shank moves with a regular motion, While the other that forms the thread on the point moves alternately at each succeeding cut with a quicker and slower motion to cut alternately on opposite sides of the thread to make the thread of gradually less depth toward the apex of the point.

Having thus described the principle or mode of operation of my said improvements and the manner of constructing and working the sam e, together with old parts so far as it was necessary to describe these latter, what I claim as my invention,and desire to secure by Letters Patent, is-

1. The employment of two cams in combination, substantially as described, for the purpose of operating the fingers which supply and present the blanks to the gripping-jaws, as described.

2. The employment of one cutter to form the thread on the conical point when combined and operating simultaneously with a second cutter for forming the thread on the main part of the shank, substantially as described and for the end specified, provided the motion of one of the cutters is extended into the track of the other to insure the making of the thread on the conical point a continuation of the thread on the main part of the shank.

THOS. J. SLOAN. Witnesses:

' WM. H. BISHOP, O. N. BAMBURGH. 

